1. Field of the Invention
The invention relates to connectors for cables having at least one wire.
2. Description of the Prior Art
A large amount of data is transmitted and processed in production installations for controlling and monitoring production processes. The continual increase in automation of manufacturing and a reduction in supervisory staff requires accurate and uncorrupted data. Electromagnetic interference and the effects of interference from sources of interference, such as electric motors and switching operations, change and corrupt control signals in data lines interconnected by plug and socket connectors.
The invention relates to a connector for a cable of a type having at least:
one wire and PA1 one screening which surrounds the wire, PA1 a housing in which are arranged
the connector having
an insulator having at least one electrical contact, and PA2 a screening contact which contacts the housing and which produces an electrically conductive connection between the housing and the screening of the cable, wherein
the screening contact is arranged to be resilient in a radial and/or axial direction and contacts the inside wall of the housing.
Connectors of this kind are known in the most diverse forms from the prior art (see, for example, U.S. Pat. No. 4,243,290 or DE 41 07 714 C1). However, these connectors have certain drawbacks. Firstly, the screening contact is usually formed by a cylindrical sleeve with a web portion surrounding it at a radial spacing therefrom and being pushed far enough under the screening braid of the cable for the front edge of the screening braid to rest against the web portion surrounding it. The housing which has previously been pushed onto the cable is then drawn up and the web portion which surrounds it at a radial spacing therefrom is pressed against the inside wall of the housing, so that an electrical contact is produced. In order to ensure that this contact has a sufficiently low contact resistance, it is necessary to make available sleeves with different diameters for the different diameter of the cables, which involves considerable expenditure in terms of manufacture and storage. Secondly, the overall operation of assembling the connector is relatively laborious and requires a high degree of manual dexterity. Finally, it is virtually impossible to assemble/take apart the connector a number of times whilst maintaining a constant contact quality for the housing, or without requiring that the cable is shortened so that the screening braid which has not yet been fanned out can be used for the contacting of the housing.
DE 37 00 514 A1 discloses a contact insert which can be inserted into a housing and which is used as a connection to earth. This contact insert is, admittedly, resiliently elastic in the radial direction. However, it serves the purpose of improving the connection to earth between the contact insert and the associated housing, and more simple replacement of the contact insert. The problem of dealing in as simple as possible a way with differences in diameter of cables on the one hand, and of the respective plug or socket connectors on the other hand, is not solved here.
DE 30 26 563 C2 discloses a spring collar with convex curvature for screening connectors which has spring fingers which are separated from each other by slits and which are screwed in screw-like manner, wherein the one longitudinal side is taller than the other. Therein, the slits are arranged alternatingly. However, one spring collar has to be manufactured for each individual diameter of cable or connector, which is very costly in terms of manufacture and storage.
DE 43 16 903 A1 discloses a contacting device for the metal braided sleeving of screened cables, by means of which contacting device the metal braided sleeving is able to be contacted in an electrically conductive manner with a connector housing. A contact member is formed by a helical spring which is pressed against the metal braided sleeving in its fitted condition and which encloses the metal braided sleeving annularly. To simplify the actual contacting and for the purpose of assembly it is provided that the helical spring is annular, encloses the metal braided sleeving of the screened cable, and consists of a sleeve-like clamping member which can be introduced into the metal braided sleeving of the screened cable and which can be latchingly engaged with the helical spring by pinching the metal braided sleeving.
DE 41 07 714 C1 discloses a coaxial connector, wherein the contacting between the cable outer conductor and a contact sleeve of the connector is effected by a contact spring, the central portion of which is held by means of an annular snap connection in such a way that it is parallel between the axes of two plastics portions. End portions which extend conically to the central axis of the contact spring or away therefrom have resilient tongue portions which are formed by slits and bear with pressure upon the cable outer conductor or contact sleeve.
Accordingly, an object of the present invention is to overcome the problems outlined hereinabove and to make available a connector which can be assembled easily and reliably with good contact making with a screening contact for cables of different diameters.